Numerical Simulation on Transient Pressure Pulsations and Complex Flow Structures of a Ultra-High-Speed Centrifugal Pump at Stalled Condition

Abstract

A high-speed centrifugal pump is the key facility to deliver oil in an aero-engine. The stable operation is quite important to the safety of the engine. High-speed pump stability is essentially caused by the transient pressure pulsations excited by the complex flow within the pump, which needs to be clarified, especially for the pump under a rotating stall condition. In the current research, unsteady pressure pulsation and the corresponding flow distribution of the high-speed centrifugal pump are analyzed using the delayed detached-eddy simulation (DDES) method. Pressure signals within the pump are extracted by monitoring points. Results show that the dominant components in the pressure spectrum exhibit a significant difference at various flow rates, which locates at the blade passing frequency fBPF under the rated working condition and deviates to five times the shaft frequency (5fn) at the stalled condition. Such phenomenon is not observed in the normal centrifugal pump with low speed when using numerical and experiment methods, and usually the amplitude at fBPF reaches the maximum. Under the stalled condition, the component at 0.2fn is generated and considered as the rotating stall frequency, which is the same at different stalled flow rates. From velocity distribution, it is found that several blade channels are stalled as characterized by the large-scale separation bubbles, which are induced and triggered by the volute tongue.

Structural Analysis and Optimization of Ultra-High-Speed Centrifugal Pump Rotor System Considering Fluid–Structure Interaction

“…An ultra-high-speed centrifugal pump is an important part of the oil supply system for an aero-engine, which provides high pressure to ensure optimal operating conditions [1,2]. However, higher speed places greater demands on the safety of the centrifugal pump system, and the complex transient flow and pressure pulsations at high-speed conditions increase system instability [3,4]. It is necessary to investigate the structure stability of the ultra-high-speed centrifugal pump to ensure the normal operation of the aero-engine.…”